An oil supply device configured to suck up oil from an oil pan by using an oil pump and supply the oil to respective portions of an engine has been known. For example, in the oil supply device disclosed in PTL 1, a bearing portion of a crank shaft is formed at a cylinder block. The oil sucked up by the oil pump flows through an oil filter and an oil cooler to be supplied to the bearing portion through oil supply passages formed at the cylinder block.